An international group of geneticists, epidemiologists and public health researchers based in Australia, France and the U.S. teamed up to study a pathogen after it caused a small but deadly outbreak of illnesses in Wisconsin.

Law enforcement officers, emergency medical workers and lab technicians are trained to minimize their exposure to dangerous substances. The increasing use of powerful opioids — which are dangerous to inhale or even touch in very small amounts — is adding unpredictability to these risks.